The present invention relates to a chain stitch sewing machine and in particular to a device for switching between a long stitch and a bunch or short stitch.
In chain stitch sewing machines of the conventional type, a switch eccentric shaft is provided for switching the machine between a long stitch and a short or bunch stitch. By varying the relative displacement between the axis of a main shaft and the axis of the eccentric shaft, the stroke of a feed dog is varied and the stitch length is effectively controlled, as shown for example in U.S. Pat. No. 3,392,692 to Reimer. This switching is usually accomplished by the operator. However, the switching operation takes the machine out of operation to effect the changeover.